In data gathering technology, and more particularly in image gathering technology, it is possible to image a given view using a number of different image gathering techniques. For example, a standard light microscope may be able to image a slide using bright field illumination and dark field illumination. Alternatively the same microscope may be used to view the same field of view using the same illumination conditions but with different light filters. A standard camera may similarly view a scene using different filters or under different illumination conditions or at different times.
The above applies to all types of image gathering techniques, including all types of electron and conventional microscopes, cameras, telescopes for all kinds of wavelengths, radar, thermal imaging devices, image intensifiers, laser ranging devices and medical imaging devices including for example, magnetic resonance imaging devices or scanners, PET scanners, x-ray devices, etc. Electron microscopes include for example scanning electron microscopes, transmission electron microscopes, and telescopes include reflecting and refracting telescopes as well as radio telescopes and x-ray and gamma ray telescopes. The devices may include high precision devices using CCD technology for image detection.
Furthermore it is often desirable to image a large field of interest which is larger than the maximum field that the device is able to image at any one time. In this case, the image is therefore viewed in parts or sections. If the field of interest is then re-imaged using a different imaging method then it is often desirable to view simultaneously the same part imaged using the two methods. It is often further desirable that one of the two images being viewed should be one that is currently being imaged. It may be desirable to view the two images side by side or alternatively to superimpose one upon the other.
The imaging device may be able to image the field of interest using any number of imaging methods. In such a case it may be desirable to view each corresponding image from each method simultaneously.
The field of interest may be an area that is too large to image all, at once or it may be a depth of field that cannot be imaged at once. Alternatively, it may be a field that varies over time or any combination of the above.
Imaging is carried out using terrestrial-based platforms, airborne platforms and space-based platforms. The same considerations apply to all of these cases.